The present invention relates generally to a controlling system for a center differential lock mechanism with an anti-lock brake system. More particularly, the present invention is concerned with a system for controlling a center differential lock mechanism in accordance with the operating condition of a throttle valve and an anti-lock brake system.
An example of a prior art control method for all-wheel driven vehicle is disclosed in U.S. Pat. No. 4,753,131 patented on Jun. 7, 1988. The vehicle comprises a drive unit, a transmission gear, a front axle-differential, a rear-axle differential and an intermediate differential. The torque of the drive unit is transmitted by way of the transmission gear to the intermediate differential. Driving shafts are operatively connected to the intermediate differential. An operating cylinder is arranged between the intermediate differential and the rear-axle differential. The intermediate differential and the rear-axle differential are provided for differential locks. The differential lock which is provided for the intermediate differential controls the transmission of the torque for the driving shafts. The differential lock which is equipped with the rear-axle differential controls the transmission of torque for rear output shafts. Two rear wheels are connected to the rear output shafts. The slip-controlled brake system includes a pedal actuated three-circuit braking pressure generator with a hydraulic energy supply and with a hydraulic accumulator. Two front wheels are connected to the front-axle shaft by way of semi-axles. The front wheels are in hydraulic communication with separate first and second brake circuits, while the rear wheels are connected jointly to the third brake circuit.
The rotational speeds of the wheels will be determined by wheel rotational sensors in the form of electric signals which are supplied to a slip control unit or to an electric circuit. Upon commencement of brake slip control or upon recognition of a locked condition braking is ensured by corresponding logic in the electric circuit.
In this related art, the slip-controlled brake system is operated in accordance with the depressing of a brake pedal. The intermediate differential is simultaneously controlled at the beginning of the depressing of the brake pedal. Based on the above mentioned controlling operation, the response time of the intermediate differential is slow. This is a problem for the controlling of the intermediate differential operation.